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WBJEE · Maths · Circle

If one of the diameters of the curve \(x^{2}+y^{2}-4 x-6 y+9=0\) is a chord of a circle with centre \((1,1),\) the radius of this circle is

  1. A 3
  2. B 2
  3. C \(\sqrt{2}\)
  4. D 1
Verified Solution

Answer & Solution

Correct Answer

(A) 3

Step-by-step Solution

Detailed explanation

Given circle \(x^{2}+y^{2}-4 x-6 y+9=0\) \(\therefore\) Centre \(=\left(-\frac{1}{2} \times(-4),-\frac{1}{2} \times(-6)\right)\) \(=(2.3)\) \(\begin{aligned} \text { Radius } &=\sqrt{(-2)^{2}+(-3)^{2}-9} \\ &=\sqrt{4+9-9} \\ &=2 \end{aligned}\)…